New Delhi: Mental health, which includes one’s psychological, emotional, and social wellbeing, has a causal effect on how successful they are at healthy ageing, finds a study published in the peer-reviewed journal Nature Human Behaviour.
As part of the study, published on 17 June, a team of researchers led by Tian-Ge Wang of the Shanghai Jiao Tong University School of Medicine in China analysed eight datasets with a minimum of 800,000 people and a maximum of 2.3 million people of European descent.
The team examined the effect of mental wellbeing on different outcomes of ageing, and found that good mental health was linked with improved resilience and longevity, which are some of the factors determining healthy ageing.
The researchers studied the impact of mental wellbeing on genetically independent phenotypes (physical or morphological attributes) of ageing, which means that the characteristics used in the study to determine healthy ageing are not linked to genetics.
The five mental wellbeing traits selected by the researchers were ‘wellbeing spectrum’, ‘life satisfaction’, ‘positive affect’, ‘neuroticism’ and ‘depressive symptoms’.
Increased life satisfaction and positive affect, which refers to the extent to which one experiences positive emotions, were found to have a positive effect on ageing phenotypes, while neuroticism, which is a personality trait associated with distress and dissatisfaction, and depressive symptoms were found to have a negative impact on the phenotypes.
The only socio-economic factor associated with all the five mental wellbeing traits was a higher income.
As many as 33 factors were identified as mediators — connections between independent variables (causal variables) and dependent variables (outcome). In other words, these factors explain how and why mental wellbeing impacts healthy ageing.
Some of the mediators identified included lifestyle factors such as smoking, sleep, and physical activity; behaviour and performance factors such as medication use, cognitive performance, and loneliness; physical function factors such as adiposity, glucose metabolism, and inflammation; and diseases such as cancer, digestive disease, attention deficit hyperactivity disorder and cardiovascular disease, among others.
Among lifestyle factors, behaviours and performances, and physical functions, antihypertensive medicine, age of smoking initiation, and television watching time had the highest impact on ageing. Among diseases, attention deficit hyperactivity disorder, coronary artery disease, ischemic heart disease, and heart failure had the greatest impact on ageing.
These findings are significant because for the first time, mediating pathways that explain how mental wellbeing influences ageing have been identified.
Mind your healthy ageing
The World Health Organization (WHO) defines healthy ageing as “the process of developing and maintaining the functional ability that enables wellbeing in older age.” This “functional ability” refers to being able to meet one’s basic needs, maintain healthy relationships, make decisions, remain mobile, and contribute to society.
By conducting a Genome Wide Association Study (GWAS), which is a technique used to identify genes associated with a particular trait, the researchers evaluated the causal influence of mental wellbeing on functional ability, which characterises healthy ageing.
After data was collected from the largest GWAS in populations of European descent to lay bare the various genetic variations that could be associated with ageing, Mendelian randomisation was then used to pinpoint the exact non-hereditary genes linked to ageing for further analysis. It is a technique used by geneticists to establish cause and effect by grouping individuals based on similarities in their genetic code.
The significance of the study is that the findings can be used to devise public health policies focused on mental wellbeing, and as information for ageing research.
However, the study is not without limitations. First, the causal interpretations which the scientists laid down in their paper still need to be tested before they can be validated. In other words, replication of the study is essential to corroborate the study’s findings.
The datasets that GWAS used only consisted of individuals of European ancestry, meaning if this study is to be generalisable in the future, similar studies must be performed with datasets that include individuals of other ethnic groups.
Granville Austin is an intern with ThePrint
(Edited by Radifah Kabir)
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